Image reject receiver

• US 20030060180A1
• Filed: 09/27/2001
• Published: 03/27/2003
• Est. Priority Date: 09/27/2001
• Status: Abandoned Application

• Current Assignee: Maryland Semiconductor Incorporated, Winbond Electronics Corporation
• Original Assignee: Maryland Semiconductor Incorporated, Winbond Electronics Corporation
• Inventors: Hall, William E., Koullias, Ico
• Application Number:
  US09/967,708
• Publication Number:
  US 20030060180A1
• Time in Patent Office: Days
• US Class Current: 455/302
• CPC Class Codes: H03D 3/008 Compensating DC offsets
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22

Abstract

An image reject receiver is provided. The image reject receiver includes a first type low-intermediate frequency receiver, a zero-intermediate frequency receiver and a second low-intermediate frequency receiver. The first type low-intermediate frequency receiver is used for receiving image signal and transferring the image signal into a mirrored image signal with a frequency used in the first low-intermediate frequency receiver. The mirrored image signal is sent to the zero-intermediate frequency receiver and is suppressed to a zero frequency. The signal with the zero frequency is outputted to the second low-intermediate frequency receiver and is then transferred to be with the second intermediate frequency for easily demodulating in the following operation.

Claims

1. An image reject receiver, using a multi-low-intermediate frequency and a zero-intermediate frequency, the image reject receiver comprising:

a first low-intermediate frequency receiver, for receiving an image signal and transferring the image signal into an mirrored image signal by using a first intermediate frequency as a carrier in the first low-intermediate frequency receiver;

a zero-intermediate frequency receiver, for receiving the mirrored image signal by using a zero-intermediate frequency as a carrier and suppressing the frequency of the mirrored image signal to zero; and

a second low-intermediate frequency receiver, for receiving the suppressed mirrored image signal outputted from the zero-intermediate frequency receiver and transferring the frequency of the suppressed mirrored image signal from zero to a second intermediate frequency.

2. An image reject receiver as described in the claim 1, wherein the zero-intermediate frequency receiver further includes a DC calibration circuit for eliminating DC offsets generated from the zero-intermediate frequency receiver.

3. An image reject receiver as described in the claim 1, further includes a demodulator, for receiving and demodulating the suppressed mirrored image signal.

4. An image reject receiver as described in the claim 1, further includes a synthesizer for providing a local oscillating signal used in the first low-intermediate frequency receiver.

5. An image reject receiver as described in the claim 4, wherein the local oscillating signal generated by the synthesizer is divided by a constant and then is used by the zero-intermediate frequency and second low-intermediate frequency receiver.

6. An image reject receiver, comprising:

a first low-intermediate frequency receiver, for receiving an image signal and transferring the image signals into a mirrored image signal by using a first intermediate frequency as a carrier;

a zero-intermediate frequency receiver, including a DC calibration circuit, for receiving the mirrored image signal with the first intermediate frequency and transferring the mirrored image signal into a suppressed mirrored image signal, wherein the DC calibration circuit is used for eliminating DC offsets generated by the zero-intermediate frequency receiver.

a second low-intermediate frequency receiver, for receiving the suppressed mirrored image signal and transferring the suppressed mirrored image signal into a signal with a second intermediate frequency used in the second low-intermediate frequency receiver; and

a synthesizer, for providing a local oscillating signal used in the first low-intermediate frequency receiver.

7. The image reject receiver as described in the claim 6, further includes a demodulator, for receiving and demodulating the signal with the second intermediate frequency.

8. The image reject receiver as described in the claim 7, wherein the frequency of local oscillating signal is generated by synthesizer is divided by a constant and is used in the zero-intermediate frequency receiver.

9. An image reject receiver, which comprising:

a first intermediate frequency receiver, for receiving an image signal and transferring the image signal into an mirrored image signal by using a first intermediate frequency as a carrier;

a zero-intermediate frequency receiver, for receiving the mirrored image signal by using a zero-intermediate frequency as a carrier and suppressing the frequency of the mirrored image signal to zero; and

a second intermediate frequency receiver, for receiving the suppressed mirrored image signal and transferring the frequency of the suppressed mirrored image signal from zero to a second intermediate frequency.

10. An image reject receiver as described in the claim 9, wherein the zero-intermediate frequency receiver further includes a DC calibration circuit for eliminating DC offsets generated from the zero-intermediate frequency receiver.

11. An image reject receiver as described in the claim 9, further includes a demodulator, for receiving and demodulating the suppressed mirrored image signal.

12. An image reject receiver as described in the claim 9, further includes a synthesizer for providing a local oscillating signal used in the first intermediate frequency receiver.

13. An image reject receiver as described in the claim 12, wherein the local oscillating signal generated by the synthesizer is divided by a constant and then is used by the zero-intermediate frequency and second intermediate frequency receiver.